Plant Immunity Inducer Development and Application.

Plant immunity inducers represent a new and rapidly developing field in plant-protection research. In this paper, we discuss recent research on plant immunity inducers and their development and applications in China. Plant immunity inducers include plant immunity-inducing proteins, chitosan oligosaccharides, and microbial inducers. These compounds and microorganisms can trigger defense responses and confer disease resistance in plants. We also describe the mechanisms of plant immunity inducers and how they promote plant health. Furthermore, we summarize the current situation in plant immunity inducer development in China and the global marketplace. Finally, we also deeply analyze the development trends and application prospects of plant immunity inducers in environmental protection and food safety.

Identification and characterization of an insect toxin protein, Bb70p, from the entomopathogenic fungus, Beauveria bassiana, using Galleria mellonella as a model system.

An insect-toxic protein, Bb70p, was purified from Beauveria bassiana 70 using ammonium sulfate precipitation, ion exchange chromatography, and gel filtration. Bb70p has a high affinity for anion exchangers and 2D electrophoresis results revealed a single spot with a molecular weight of 35.5 kDa and an iso-electric point of ∼4.5. Bb70p remains active from 4 to 60°C, within a pH range of 4-10, but is more active in slightly acidic pH. A pure protein, Bb70p does not have any carbohydrate side chains. The protein caused high mortality by intra-haemocelic injection into Galleria mellonella with LD50 of 334.4 µg/g body weight and activates the phenol oxidase cascade. With a partial amino acid sequence comparison using the NCBI database, we showed no homology to known toxin proteins of entomopathogenic fungi. Thus, Bb70p appears to be an insect toxin protein, demonstrating novelty. Identification of this insect-toxic protein presents potential to enhance the virulence of B. bassiana through genetic manipulation.

Extracellular expression of protein elicitor PeaT1 in Bacillus subtilis to enhance drought tolerance and growth in wheat / 生物工程学报

PeaT1, a protein elicitor from Alternaria tenuissima can promote plant growth and trigger systemic acquired resistance in plants. In order to expand the application of PeaT1, P43 promoter sequence and nprB signal peptide-encoding sequence were cloned from Bacillus subtilis 168 chromosomal DNA. The two sequences and peaT1 gene were spliced by overlapping extension. This product was cloned into the Escherichia coli-B. subtilis shuttle vector pHY300-PLK and the resultant recombinant expression vector (pHY43N- peaTI) plasmid was transformed into B. subtilis WB800. SDS-PAGE and Western blotting analysis showed that protein elicitor PeaT1 was expressed extracellularly in B. subtilis. This recombinant bacterial strain enhanced drought tolerance and promoted seedling growth in wheat.

Expression of a protein elicitor pebC1 from Botrytis cinerea in Pichia pastoris / 生物工程学报

In order to express PebC1 in Pichia pastoris, the pebC1 sequence was amplified from genome Botrytis cinerea BC-4-2-2-1 by PCR and subcloned into the Pichua pastoris expression vector pPIC9K to generate pPIC9K-pebC1. The recombinant plasmid was linearized by Bgl II and transformed into Pichia pastoris GS115 by electroporation. Recombinant Pichia pastoris GS115/pPIC9K-pebC1 was screened by MD and G418-YPD plates and further confirmed by PCR. The protein expression was induced by methanol and analyzed by SDS-PAGE. SDS-PAGE analysis showed a special band about 39 kDa and western blotting indicated a good antigenicity of the expressed protein. Bioassay results showed that the recombinant protein PebC1 can induce resistance to gray mould disease of cucumber and Arabidopsi thaliana.

Expression of peaT1 gene from Alternaria tenuissima in Pichia pastoris and its function / 生物工程学报

In this study, peaT1 gene was subcloned into the Pichia pastoris expression vector pPIC9K, which contained both the methanol-inducible promoter and the transcription terminator of the AOX1 gene, resulting the plasmid pPIC9K-peaT1. The recombinant plasmid was linearized by Sal I or Bgl II and transformed into P. pastoris GS115 by electroporation method. Recombinant strain was screened by Minimal Dextrose Medium and further confirmed by PCR. The gene was in frame integrated into the Pichia genome through homologous recombination, resulting the recombinant strain. Regulated by the alpha-Factor, promoter of AOX1 gene and termination signal of yeast genomic, the recombinant protein was expressed and secreted into the supernatant. The SDS-PAGE analysis indicated that the apparent molecular weight of target protein was about 35 kD. Bioassay results showed that the inhibition rate of the expressed protein against TMV was 30.37%. The supernatant was collected and then purified by anion exchange chromatography. This protein can promote seedling growth of wheat obviously.

Chemical constituents of Periploca forrestii and their cytotoxicity activity / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the chemical constituents of the roots of Periploca forrestii and evaluate their cytotoxicity activities.</p><p><b>METHOD</b>Silica gel column chromatography was employed for the isolation and purification of chemical constituents. The structures were identified on the basis of spectral data and the cytotoxicities of compounds 2-4 were investigated by several tumors cell lines including blood tumor (HL-60, CCRT-CEM), prostate tumor (PC-3, DU-145) and Melanoma (UACC-62).</p><p><b>RESULT</b>Four compounds were isolated and identified as follows, lupeol-20(29)-en-3-nonadecanoate (1), peroiforoside I (2), 3beta,5beta,14beta-3OH-8beta-H-car-20(22)-enolide (3), perplocin (4).</p><p><b>CONCLUSION</b>Compound 1 is a new lupane triterpene fatty acid ester. Compounds 2-4 showed notable cytotoxicity against all tumor lines.</p>

[Construction of cDNA library of Magnaporthe grisea with magnetic bead].

OBJECTIVE: We constructed cDNA library of Magnaporthe grisea. The good quality cDNA library could facilitate finding proteinaceous elicitors of M. grisea, and elucidating the mechanisms of the M. grisea--rice interaction. METHODS: The Oligo(dT) combined with the magnetic bead was used to extract mRNA from total RNA of Magnaporthe grisea and as primers to synthesize the first-strand cDNA. Terminal transferase introduced PolyA into 3'terminal of the first cDNA strand, then the PolyA was used for amplifying the second-strand cDNA. Restriction enzyme and adapter were avoided in this research, which could solve technical limitation of the traditional method. Because all reactions were done in one centrifuge tube, this process could reduce the risk of cDNA loss and cross-contamination. The primers designed in this research could clone the amplified cDNAs into expression vector in a desirable orientation. RESULTS: The cDNA library constructed had a high titer of 8.9 x 10(6) cfu/mL, and contained a total clones of 8.9 x 10(7) cfu, with an average inserts size of about 1380 bp. CONCLUSION: Constructing cDNA library with magnetic bead was a highly efficient method using only small amount of experimental materials within a short period.

Method for studying traditional Chinese compound prescription / 中西医结合学报

Treatment with traditional Chinese medicinal composite is one of the most important characteristics of traditional Chinese medicine (TCM). Studying material base of TCM composite and its mechanism is a key to modernizing the industry of Chinese medicinal herbs. The research for TCM composite can be carried out from many different angles, including multiple components, multiple actions, multiple levels and multiple targets. Such a way to study TCM composite will be beneficial to improving the theory of TCM composite, guiding clinical administration and developing new products.